update-java-alternatives 命令

常用示例

说明

update-java-alternatives manages multiple Java installations on Debian and Ubuntu systems. It is a wrapper around the update-alternatives system specifically designed for Java, updating all Java-related binaries (java, javac, jar, javadoc, etc.) simultaneously. When switching Java versions, this tool ensures all associated commands point to the same installation, preventing version mismatches between the JRE and JDK tools. This is essential for development environments that require specific Java versions. The jname parameter corresponds to the directory name under /usr/lib/jvm/ for the Java installation. Use --list to see available installations and their names. The tool is part of the java-common package on Debian-based systems.

参数

-l, --list _jname_

List all installed Java packages, or details about a specific installation.

-s, --set _jname_

Set all alternatives to the specified Java installation.

-a, --auto

Switch all alternatives to automatic mode, letting the system choose the highest priority version.

--jre

Limit actions to runtime environment alternatives only, not development kit tools.

--jre-headless

Limit actions to headless runtime alternatives (no GUI support).

--plugin

Limit actions to browser plugin alternatives.

-t, --test

Dry run mode. Show what would be done without making changes.

-h, --help

Display help message.